CN107104773B

CN107104773B - Adaptive control channel design for balancing data payload size and decoding time

Info

Publication number: CN107104773B
Application number: CN201611042235.2A
Authority: CN
Inventors: P·加尔
Original assignee: Qualcomm Inc
Current assignee: Qualcomm Inc
Priority date: 2011-10-03
Filing date: 2012-10-03
Publication date: 2020-09-08
Anticipated expiration: 2032-10-03
Also published as: JP6612299B2; KR20140070653A; KR101581713B1; JP2014530575A; US10516518B2; CN107104773A; CN103959702A; EP2764653B1; WO2013052103A3; JP2018050312A; JP2016197868A; IN2014CN02711A; EP2764653A2; CN103959702B; US20170163397A1; US20130083666A1; WO2013052103A2; US9614654B2

Abstract

Adaptive control channel design for balancing data payload size and decoding time. The method for wireless communication includes: the transport block is allocated to the control channel region according to the size of the transport block. A User Equipment (UE) monitors at least two different control regions in a subframe for control information. The monitored control regions do not overlap in time. The UE receives a subframe including control information in at least one of the two different control regions.

Description

Adaptive control channel design for balancing data payload size and decoding time

The application is a divisional application of Chinese patent application with application number 201280059117.6(PCT/US2012/000450), application date 2012, 12/3, entitled "adaptive control channel design for balancing data payload size and decoding time".

Cross Reference to Related Applications

This application is based on the 35u.s.c. § 119(e) claiming the benefit of U.S. provisional patent application No.61/542,764 entitled "ADAPTIVE CONTROL CHANNEL DESIGN FOR bearing DATA panel SIZE AND decoding, filed on 3/10/2011, the disclosure of which is expressly incorporated herein by reference in its entirety.

Technical Field

Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to allocating transport blocks to control channel regions according to sizes of the transport blocks.

Background

Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasting. Typical wireless communication systems may employ multiple-access techniques capable of supporting communication with multiple users by sharing the available system resources (e.g., bandwidth, transmit power). Examples of such multiple-access techniques include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, single carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

These multiple access techniques have been adopted in various telecommunications standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. An example of an emerging telecommunications standard is Long Term Evolution (LTE). LTE is an enhanced set of Universal Mobile Telecommunications System (UMTS) mobile standards promulgated by the third generation partnership project (3 GPP). It is designed to better support mobile broadband internet access by improving spectral efficiency, lower cost, improve services, utilize new spectrum, and better combine with other open standards that use OFDMA on the Downlink (DL), SC-FDMA on the Uplink (UL), and multiple-input multiple-output (MIMO) antenna technology. However, as the demand for mobile broadband access is increasing, there is a need for further improvements in LTE technology. Preferably, these improvements should be applicable to other multiple access techniques and telecommunications standards employing these techniques.

The features and technical advantages of the present disclosure have been summarized here rather broadly in order that the detailed description that follows may be better understood. Additional features and advantages of the disclosure will be described hereinafter. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the teachings of the disclosure as set forth in the appended claims. The novel features which are believed to be characteristic of the disclosure, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present disclosure.

Disclosure of Invention

In one aspect, a method for wireless communication is disclosed. The method comprises the following steps: monitoring at least two different control regions in a subframe for control information, wherein the two control regions do not overlap in time. The method further comprises the following steps: receiving the subframe including control information in at least one of the two different control regions.

Another aspect discloses a method for wireless communication, the method comprising: a control region for transmitting control information to a receiving side is determined based on the transport block size. The method further comprises the following steps: transmitting control information in the determined control region.

In another aspect, wireless communications are disclosed having a memory and at least one processor coupled to the memory. The processor is configured to monitor at least two different control regions in a subframe for control information. The two control regions do not overlap in time. The processor is further configured to receive the subframe including control information in at least one of the two different control regions.

Another aspect discloses wireless communications having a memory and at least one processor coupled to the memory. The processor is configured to determine a control region for transmitting control information to a receiving side based on a transport block size. The processor is further configured to transmit control information in the determined control region.

In another aspect, a computer program product for wireless communication in a wireless network is disclosed, the computer program product having a non-transitory computer-readable medium. The computer readable medium has non-transitory program code recorded thereon, which when executed by a processor, causes the processor to: monitoring at least two different control regions in a subframe for control information, wherein the two control regions do not overlap in time. The program code also causes the processor to receive the subframe including control information in at least one of the two different control regions.

Another aspect discloses a computer program product for wireless communication in a wireless network, the computer program product having a non-transitory computer-readable medium. The computer readable medium has non-transitory program code recorded thereon, which when executed by a processor, causes the processor to: a control region for transmitting control information to a receiving side is determined based on the transport block size. The program code also causes the processor to transmit control information in the determined control region.

In another aspect, an apparatus is disclosed, the apparatus comprising: means for monitoring at least two different control regions in a subframe for control information. The monitored control regions do not overlap in time. Further comprising: means for receiving the subframe including control information in at least one of the two different control regions.

Another aspect discloses an apparatus, comprising: the apparatus includes means for determining a control region for transmitting control information to a receiving side based on a transport block size. Further comprising: means for transmitting control information in the determined control region.

Additional features and advantages of the disclosure will be described hereinafter. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the teachings of the disclosure as set forth in the appended claims. The novel features which are believed to be characteristic of the disclosure, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present disclosure.

Drawings

The features, nature, and advantages of the present disclosure will become more apparent from the detailed description set forth below when taken in conjunction with the drawings in which like reference characters identify correspondingly throughout.

Fig. 1 is a diagram showing an example of a network architecture.

Fig. 2 is a diagram illustrating an example of an access network.

Fig. 3 is a diagram showing an example of a downlink frame structure in LTE.

Fig. 4 is a diagram showing an example of an uplink frame structure in LTE.

Fig. 5 is a diagram showing an example of a radio protocol architecture for the user plane and the control plane.

Fig. 6 is a diagram illustrating an example of an evolved node B and user equipment in an access network.

Fig. 7 shows an example of an enhanced physical downlink control channel.

FIG. 8 illustrates a block diagram depicting a resource arrangement in accordance with aspects of the present disclosure.

Fig. 9A and 9B are block diagrams illustrating a method for allocating a transport block to a control channel region.

Fig. 10 and 11 are conceptual data flow diagrams illustrating the data flow between different modules/means/components in an exemplary apparatus.

Fig. 12 and 13 are block diagrams illustrating different modules/units/components in an exemplary apparatus.

Detailed Description

The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details in order to provide a thorough understanding of the various concepts. It will be apparent, however, to one skilled in the art that these concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

Aspects of a telecommunications system are presented with reference to various apparatus and methods. These apparatus and methods are described in the following detailed description and illustrated in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms, etc. (collectively referred to as "elements"). These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

For example, an element or any portion of an element or any combination of elements may be implemented with a "processing system" that includes one or more processors. Examples of processors include microprocessors, microcontrollers, Digital Signal Processors (DSPs), Field Programmable Gate Arrays (FPGAs), Programmable Logic Devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functions described throughout this disclosure. One or more processors in the processing system may execute software. Software shall be construed broadly to mean instructions, instruction sets, code segments, program code, programs, subprograms, software modules, applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

Thus, in one or more exemplary embodiments, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored or encoded as one or more instructions or code on a computer-readable medium. Computer readable media includes computer storage media. A storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Disk and disc, as used herein, includes Compact Disc (CD), laser disc, optical disc, Digital Versatile Disc (DVD), floppy disk and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

Fig. 1 is a diagram illustrating an LTE network architecture 100. The LTE network architecture 100 may be referred to as an Evolved Packet System (EPS) 100. The EPS 100 may include one or more User Equipment (UE)102, an evolved UMTS terrestrial radio access network (E-UTRAN)104, an Evolved Packet Core (EPC)110, a Home Subscriber Server (HSS)120, and operator IP services 122. The EPS may interconnect with other access networks, but those entities/interfaces are not shown for the sake of brevity. As shown, the EPS provides packet switched services, however, as those skilled in the art will readily appreciate, the various concepts presented throughout this disclosure may be extended to networks providing circuit switched services.

The E-UTRAN includes evolved node Bs (eNodeBs) 106 and other eNodeBs 108. The eNodeB 106 provides user and control plane protocol terminations to the UE 102. The eNodeB 106 may be connected to other enodebs 108 via a backhaul (e.g., an X2 interface). The eNodeB 106 may also be referred to as a base station, a base station transceiver, a radio base station, a radio transceiver, a transceiver function, a Basic Service Set (BSS), an Extended Service Set (ESS), or some other suitable terminology. The eNodeB 106 provides the UE102 with an access point to the EPC 110. Examples of UEs 102 include cellular phones, smart phones, Session Initiation Protocol (SIP) phones, laptops, Personal Digital Assistants (PDAs), satellite radios, global positioning systems, multimedia devices, video devices, digital audio players (e.g., MP3 players), cameras, game consoles, or any other similar functioning devices. UE102 may also be referred to by those skilled in the art as a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.

The enodebs 106 are connected to the EPC 110 via, for example, an S1 interface. EPC 110 includes Mobility Management Entity (MME)112, other MMEs 114, serving gateway 116, and Packet Data Network (PDN) gateway 118. MME 112 is a control node that handles signaling between UE102 and EPC 110. Generally, the MME 112 provides bearer and connection management. All user IP packets are transmitted through the serving gateway 116, the serving gateway 116 itself being connected to the PDN gateway 118. The PDN gateway 118 provides UE IP address allocation as well as other functions. The PDN gateway 118 connects to the operator's IP service 122. The operator's IP services 122 may include the internet, intranets, IP Multimedia Subsystem (IMS), and PS streaming services (PSs).

Fig. 2 is a diagram illustrating an example of an access network 200 in an LTE network architecture. In this example, the access network 200 is divided into several cellular regions (cells) 202. One or more lower power class enodebs 208 may have cellular regions 210 that overlap with one or more of the cells 202. The lower power class eNodeB 208 may be a Remote Radio Head (RRH), a femto cell (e.g., a home eNodeB (henodeb)), a pico cell, or a micro cell. The macro enodebs 204 are each assigned to a respective cell 202 and are configured to provide an access point to the EPC 110 for all UEs 206 in the cells 202. While there is no centralized controller in this example of the access network 200, a centralized controller may be used in alternative configurations. The eNodeB204 is responsible for all radio related functions including radio bearer control, admission control, mobility control, scheduling, security, and connectivity to the serving gateway 116.

The modulation and multiple access schemes used by the access network 200 may vary depending on the particular telecommunications standard being deployed. In LTE applications, OFDM is used on the downlink and SC-FDMA is used on the uplink to support both Frequency Division Duplex (FDD) and Time Division Duplex (TDD). As will be readily appreciated by those skilled in the art from the following detailed description, the various concepts presented herein are well suited for LTE applications. However, these concepts can be readily extended to other telecommunications standards using other modulation and multiple access techniques. These concepts may be extended to evolution data optimized (EV-DO) or Ultra Mobile Broadband (UMB), for example. EV-DO and UMB are air interface standards promulgated by the third generation partnership project 2(3GPP2) as part of the CDMA2000 family of standards and employ CDMA to provide broadband internet access to mobile stations. These concepts can also be extended to: universal Terrestrial Radio Access (UTRA) using wideband CDMA (W-CDMA) and other variants of CDMA (e.g., TD-SCDMA); global system for mobile communications (GSM) using TDMA; and evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11(Wi-Fi), IEEE 802.16(WiMAX), IEEE 802.20, and Flash-OFDM employing OFDMA. UTRA, E-UTRA, UMTS, LTE, and GSM are described in documents from the 3GPP organization. CDMA2000 and UMB are described in documents from the 3GPP2 organization. The actual wireless communication standard and multiple access technique employed will depend on the specific application and the overall design constraints imposed on the system.

The eNodeB204 may have multiple antennas supporting MIMO technology. The use of MIMO technology may enable the eNodeB204 to utilize the spatial domain to support spatial multiplexing, beamforming, and transmit diversity. Spatial multiplexing may be used to transmit different data streams simultaneously on the same frequency. The data stream may be sent to a single UE206 to increase the data rate or to multiple UEs 206 to increase the overall system capacity. This is achieved by spatially precoding each data stream (i.e., applying a scaling of amplitude and phase) and then transmitting each spatially precoded stream through multiple transmit antennas on the downlink. The spatially precoded data streams arrive at UEs 206 with different spatial signatures (spatial signatures), which enables each UE206 to recover one or more data streams destined for that UE 206. On the uplink, each UE206 transmits a spatially precoded data stream, which enables the eNodeB204 to identify the source of each spatially precoded data stream.

Spatial multiplexing is typically used when channel conditions are good. When channel conditions are not as good, beamforming may be used to concentrate the transmission energy in one or more directions. This may be achieved by spatially precoding data for transmission via multiple antennas. To achieve good coverage at the edges of the cell, single stream beamforming transmission may be used in conjunction with transmit diversity.

In the following detailed description, various aspects of an access network will be described with reference to a MIMO system supporting OFDM on the downlink. OFDM is a spread spectrum technique that modulates data over several subcarriers within an OFDM symbol. The subcarriers are spaced apart at precise frequencies. This spacing provides "orthogonality" so that the receiver can recover the data from the subcarriers. In the time domain, a guard interval (e.g., a cyclic prefix) may be added to each OFDM symbol to overcome OFDM inter-symbol interference. The uplink may use SC-FDMA in the form of DFT-spread OFDM signals to compensate for high peak-to-average power ratio (PAPR).

Fig. 3 is a diagram 300 illustrating an example of a downlink frame structure in LTE. A frame (10ms) may be divided into 10 equally sized subframes. Each subframe may include two consecutive slots. A resource grid may be used to represent two slots, each slot comprising a resource block. The resource grid is divided into a plurality of resource units. In LTE, a resource block contains 12 consecutive subcarriers in the frequency domain and 7 consecutive OFDM symbols in the time domain, or 84 resource elements, for a conventional cyclic prefix in each OFDM symbol. For an extended cyclic prefix, a resource block contains 6 consecutive OFDM symbols in the time domain and has 72 resource elements. Some of the resource elements (as indicated by R302, 304) include downlink reference signals (DL-RS). The DL-RS includes cell-specific RS (crs) (also sometimes referred to as common RS)302 and UE-specific RS (UE-RS) 304. The UE-RS304 transmits only on the resource blocks to which the corresponding Physical Downlink Shared Channel (PDSCH) is mapped. The number of bits carried by each resource unit depends on the modulation scheme. Thus, the more resource blocks the UE receives and the higher the modulation scheme, the higher the data rate for the UE.

Fig. 4 is a diagram 400 illustrating an example of an uplink frame structure in LTE. The available resource blocks for the uplink may be divided into a data portion and a control portion. The control portion may be formed at both edges of the system bandwidth and may have a configurable size. The resource blocks in the control portion may be allocated to the UE for transmission of control information. The data portion may include all resource blocks not included in the control portion. The uplink frame structure produces a data portion that includes contiguous subcarriers, which may allow a single UE to be assigned all of the contiguous subcarriers in the data portion.

The resource blocks 410a, 410b in the control section may be allocated to the UE to send control information to the eNodeB. The resource blocks 420a, 420b in the data portion may also be allocated to the UE to transmit data to the eNodeB. The UE may send control information in a Physical Uplink Control Channel (PUCCH) on the resource blocks allocated in the control portion. The UE may send only data or both data and control information in a Physical Uplink Shared Channel (PUSCH) on the allocated resource blocks in the data portion. The uplink transmission may span two slots of a subframe and may hop in frequency.

A set of resource blocks may be used to perform initial system access and achieve uplink synchronization in a Physical Random Access Channel (PRACH) 430. The PRACH 430 carries a random sequence and may not carry any uplink data/signaling. Each random access preamble occupies a bandwidth corresponding to 6 consecutive resource blocks. The starting frequency is specified by the network. That is, the transmission of the random access preamble is limited to a specific time and frequency resource. There is no frequency hopping for PRACH. PRACH attempts are carried in a single subframe (1ms) or in a series of several consecutive subframes, and a UE can only make a single PRACH attempt per frame (10 ms).

Fig. 5 is a diagram 500 illustrating an example of radio protocol architecture for the user plane and the control plane in LTE. The radio protocol architecture for the UE and eNodeB is shown with three layers: layer 1, layer 2 and layer 3. Layer 1 (layer L1) is the lowest layer and performs various physical layer signal processing functions. The L1 layer will be referred to herein as the physical layer 506. Layer 2(L2 layer) 508 is higher than physical layer 506 and is responsible for the link between the UE and the eNodeB over physical layer 506.

In the user plane, the L2 layer 508 includes a Medium Access Control (MAC) sublayer 510, a Radio Link Control (RLC) sublayer 512, and a Packet Data Convergence Protocol (PDCP)514 sublayer, which terminate at the eNodeB on the network side. Although not shown, the UE may have several upper layers above the L2 layer 508, including a network layer (e.g., IP layer) that terminates at the PDN gateway 118 on the network side and an application layer that terminates at the other end of the connection (e.g., far end UE, server, etc.).

The PDCP sublayer 514 provides multiplexing between different radio bearer channels and logical channels. The PDCP sublayer 514 also provides header compression for upper layer data packets to reduce radio transmission overhead, security by ciphering the data packets, and handover support for UEs between enodebs. The RLC sublayer 512 provides segmentation and reassembly of upper layer data packets, retransmission of lost data packets, and reordering of data packets to compensate for out-of-order reception due to hybrid automatic repeat request (HARQ). The MAC sublayer 510 provides multiplexing between logical channels and transport channels. The MAC sublayer 510 is also responsible for allocating various radio resources (e.g., resource blocks) among UEs in one cell. The MAC sublayer 510 is also responsible for HARQ operations.

In the control plane, the radio protocol architecture for the UE and eNodeB is substantially the same for the physical layer 506 and the L2 layer 508, except that there is no header compression function for the control plane. The control plane also includes a Radio Resource Control (RRC) sublayer 516 in layer 3 (layer L3). The RRC sublayer 516 is responsible for acquiring radio resources (i.e., radio bearers) and for configuring lower layers using RRC signaling between the eNodeB and the UE.

Fig. 6 is a block diagram of an eNodeB610 in an access network in communication with a UE 650. In the downlink, upper layer packets from the core network are provided to a controller/processor 675. The controller/processor 675 implements the functionality of the L2 layer. In the downlink, the controller/processor 675 provides header compression, ciphering, packet segmentation and reordering, multiplexing between logical and transport channels, and radio resource allocation to the UE 650 based on various priority metrics. The controller/processor 675 is also responsible for HARQ operations, retransmission of lost packets, and signaling to the UE 650.

TX processor 616 performs various signal processing functions for the L1 layer (i.e., the physical layer). The signal processing functions include: coding and interleaving to facilitate Forward Error Correction (FEC) at the UE 650, and mapping to signal constellations based on various modulation schemes (e.g., binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), M-phase-shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). The coded and modulated symbols are then split into parallel streams. Each stream is then mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., pilot) in the time and/or frequency domain, and then combined together using an Inverse Fast Fourier Transform (IFFT) to produce a physical channel carrying a time-domain OFDM symbol stream. The OFDM streams are spatially precoded to generate a plurality of spatial streams. The channel estimates from channel estimator 674 may be used to determine coding and modulation schemes and for spatial processing. The channel estimate may be derived from a reference signal and/or channel condition feedback sent by the UE 650. Each spatial stream is then provided to a different antenna 620 via a respective transmitter 618 TX. Each transmitter 618TX modulates a radio frequency carrier with a respective spatial stream for transmission.

At the UE 650, each receiver 654RX receives a signal through its respective antenna 652. Each receiver 654RX recovers information modulated onto a radio frequency carrier and provides the information to a Receiver (RX) processor 656. The RX processor 656 performs various signal processing functions at the L1 layer. The RX processor 656 performs spatial processing on the information to recover any spatial streams designated for the UE 650. If multiple spatial streams are designated for the UE 650, they may be combined into a single OFDM symbol stream by the RX processor 656. The RX processor 656 then converts the OFDM symbol stream from the time-domain to the frequency domain using a Fast Fourier Transform (FFT). The frequency domain signal comprises a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier are recovered and demodulated from the reference signal by determining the most likely signal constellation points transmitted by the eNodeB 610. These soft decisions may be based on channel estimates computed by a channel estimator 658. The soft decisions are then decoded and deinterleaved to recover the data and control signals that were originally transmitted by the eNodeB610 on the physical channel. The data and control signals are then provided to a controller/processor 659.

The controller/processor 659 implements the L2 layer. The controller/processor 659 may be associated with a memory 660 that stores program codes and data. The memory 660 may be referred to as a computer-readable medium. In the uplink, the controller/processor 659 provides demultiplexing between transport and logical channels, reassembly of packets, deciphering, header decompression, control signal processing to recover upper layer packets from the core network. The upper layer packets are then provided to a data sink 662, the data sink 662 representing all protocol layers above the L2 layer. Various control signals may also be provided to the data sink 662 for L3 processing. The controller/processor 659 also uses an Acknowledgement (ACK) and/or Negative Acknowledgement (NACK) protocol to account for error detection to support HARQ operations.

In the uplink, a data source 667 is used to provide upper layer packets to the controller/processor 659. The data source 667 represents all protocol layers above the L2 layer. Similar to the functionality described in connection with the downlink transmission by the eNodeB610, the controller/processor 659 implements the L2 layer for the user plane and the control plane by providing header compression, ciphering, packet segmentation and reordering, and multiplexing between logical and transport channels based on radio resource allocations by the eNodeB 610. The controller/processor 659 is also responsible for HARQ operations, retransmission of lost packets, and signaling to the eNodeB 610.

Channel estimates, derived by a channel estimator 658 from a reference signal or feedback sent by the eNodeB610, may be used by the TX processor 668 to select the appropriate coding and modulation schemes, as well as to facilitate spatial processing. The spatial streams generated by the TX processor 668 are provided to different antennas 652 via separate transmitters 654 TX. Each transmitter 654TX modulates a radio frequency carrier with a respective spatial stream for transmission.

The uplink transmissions are processed at the eNodeB610 in a manner similar to that described in connection with the receiver function at the UE 650. Each receiver 618RX receives a signal through its respective antenna 620. Each receiver 618RX recovers information modulated onto a radio frequency carrier and provides the information to an RX processor 670. RX processor 670 may implement the L1 layer.

The controller/processor 675 implements the L2 layer. The controller/processor 675 can be associated with a memory 676 that stores program codes and data. The memory 676 may be referred to as a computer-readable medium. In the uplink, the controller/processor 675 provides demultiplexing between transport and logical channels, reassembly of packets, deciphering, header decompression, control signal processing to recover upper layer packets from the UE 650. Upper layer packets from the controller/processor 675 may be provided to a core network. The controller/processor 675 may also use ACK and/or NACK protocols to account for error detection to support HARQ operations.

In

LTE releases

8, 9 and 10, the Physical Downlink Control Channel (PDCCH) is located within the first few symbols (e.g., 1, 2, 3 or 4) in a subframe and is fully distributed over the entire system bandwidth. Furthermore, the physical downlink control channel is Time Domain Multiplexed (TDM) with the shared control channel (e.g., PDSCH), which effectively divides the subframe into a control region and a data region.

In release 11, a coordinated multipoint transmission (CoMP) scheme is supported. This feature provides an interference mitigation technique for improving overall communication performance. With CoMP, multiple base stations (e.g., enodebs 110) cooperate to transmit data to one or more UEs on the downlink and/or receive data from one or more UEs on the uplink. Downlink CoMP and uplink CoMP may be separately or jointly enabled for the UE. Some examples of CoMP schemes are described below. In joint transmission (for downlink CoMP), multiple enodebs transmit the same data to the UE. In joint reception (for uplink CoMP), multiple enodebs receive the same data for a UE. In cooperative beamforming, an eNodeB transmits to its UEs using beams selected to reduce interference to UEs in neighboring cells. In dynamic point selection, the cells participating in data transmission may vary from subframe to subframe. CoMP can exist in homogeneous and/or heterogeneous networks (hetnets). The connection between the nodes participating in CoMP may be X2 or fiber. In heterogeneous network CoMP, the low power nodes may include Remote Radio Heads (RRHs).

Conventional physical downlink control channels do not include sufficient control capacity for coordinated multipoint (CoMP) scenarios. In particular, CoMP scenario 4 occurs when a macro eNodeB and a connected Remote Radio Head (RRH) transmit potentially different data using the same cell identity but in a coordinated manner.

Enhanced physical downlink control channel (ePDCCH) may improve control link performance for downlink coverage enhancement and may also provide a control channel solution for the extension carrier. The extension carrier is a non-independent carrier that may not specify a legacy control region.

Those skilled in the art will appreciate that physical downlink control channel enhancements techniques have included: using a new control region, connecting efficiency gains with waveform shaping, using higher order modulation to reserve resources, and multi-user multiple-input multiple-output (MU-MIMO) multiplexing.

LTE release 11 includes enhanced physical downlink control channels and other channels (e.g., enhanced pcfich (epcfich) and enhanced phich (ephich)). In contrast to a conventional PDCCH (e.g., legacy PDCCH) which occupies the first few control symbols in a subframe, the enhanced physical downlink control channel occupies the data portion of the subframe, similar to the PDSCH. The enhanced physical downlink control channel may increase control channel capacity, support frequency-domain inter-cell interference coordination (ICIC), improve spatial reuse of control channel resources, support beamforming and/or diversity, and operate on new carrier types and in MBSFN subframes. Furthermore, the enhanced physical downlink control channel may co-exist on the same carrier as the legacy UE.

Fig. 7 shows various enhanced physical downlink control channel structures (Alt 1-Alt 5). For example, in some cases, the enhanced physical downlink control channel structure may be the same as the R-PDCCH structure (Alt 1). Alternatively, the enhanced physical downlink control channel may be Frequency Division Multiplexed (FDM) (Alt 2) with the data region. Further, in an alternative structure, the enhanced physical downlink control channel structure may be Time Division Multiplexed (TDM) with the data region (Alt 3). Alternatively, the enhanced physical downlink control channel may be similar but not identical to the R-PDCCH (Alt 4). In another alternative structure, an enhanced physical downlink control channel may combine TDM and FDM (Alt 5). For example, downlink grants may be time division multiplexed with the data region, while uplink grants may be frequency division multiplexed with the data region.

The present disclosure provides aspects for mapping an enhanced physical downlink control channel in the presence of other signals. The other signals may potentially include: common Reference Signals (CRS), legacy control regions, PSS/SSS, PBCH, PRS (positioning reference signal), channel state information reference signals (CSI-RS), and/or demodulation reference signals (DM-RS).

FIG. 8 illustrates a block diagram of a resource arrangement in accordance with aspects of the present disclosure. A block includes a data subframe 810 and a control subframe 812. The control subframe 812 includes two

slots

814 and 816, and each

slot

814 and 816 includes a resource unit. That is, each slot includes 7 OFDM symbols in the time domain and 12 subcarriers in the frequency domain, and each slot includes resource units that can be grouped as Resource Blocks (RBs). Within the slot of the control subframe 812, a legacy control region (PDCCH) is allocated to the first 1, 2, or 3 OFDM symbols as previously discussed. In some cases, e.g., 1.4MHz bandwidth, the legacy control region is allocated to the first 4 OFDM symbols. According to aspects of the present disclosure, a new control region (ePDCCH) is allocated to resource elements of one or more slots not allocated by a legacy control region, CRS, or DM-RS.

As shown in fig. 8, according to an aspect, the legacy control region is allocated to the first 3 OFDM symbols of the control subframe 812. In addition, some of the resource elements of the first and

second slots

814 and 816 are allocated to CRS and DM-RS. Finally, a new control region is allocated to the remaining resource units of the first time slot 814 and the remaining resource units of the second time slot 816. The remaining resource elements refer to resource elements that are not allocated to a legacy control region, CRS, or DM-RS.

Although fig. 8 illustrates a new control region occupying all remaining resource units of the first and second slots, the present disclosure is not limited to a new control region occupying all remaining resource units of the subframe. In particular, a new control region may be allocated to some or all of the remaining resource units of the first time slot and/or the second time slot. Further, aspects of the present disclosure provide for a new control region occupying resource units of one or two slots, however, the new control region may be divided into other sizes and is not limited to two slots of a subframe.

In

LTE releases

8, 9 and 10, the turnaround time for a UE Acknowledgement (ACK) is 4 ms. For example, if the PDCCH and PDSCH are transmitted to the UE in subframe n, the UE may transmit a positive or negative ACK in subframe n + 4. According to an aspect, the decoding time for a new control region is reduced. For example, the decoding time can be reduced to 2.5-3 ms. Specifically, if the new control region occupies only the unoccupied resource units in the first slot, the decoding time is reduced to about 3 ms. Furthermore, if the new control region occupies unoccupied resource units in the second slot or both the first and second slots, the decoding time is reduced to about 2.5-3 ms.

It should be noted that in conventional systems, reduced decoding time can only be achieved by redesigning the demodulation back-end hardware. Thus, aspects of the present disclosure provide for reduced decoding time without hardware modification.

In one aspect, a maximum Transport Block Size (TBS) is limited as a function of available decoding time. For example, for a legacy control region, the maximum transport block size (Max _ TBS) may be expressed as:

Max_TBS＝C_max(1)

for a new control region, when the new control region occupies resource units of only the first slot, the maximum transport block size may be expressed as follows:

Max_TBS＝C_max/x (2)

further, for a new control region, when the new control region occupies resource units of the first and second slots, the maximum transport block size may be expressed as follows:

Max_TBS＝C_max/y (3)

in

equations

1, 2 and 3, C_maxIs the maximum transport block size allowed by the UE class. The parameters x and y are selected parameters, where x and y are both greater than or equal to 1. The parameters x and y may be selected based on various factors (e.g., new control region decoding time, symbol pre-processing time, MIMO mode, transmission rank, or use of UE interference cancellation).

Although the maximum transmission size specifies which time slot may be used, the specification is not exclusive. For example, even if the maximum transport block size specifies that the second time slot is used for a new control region, the transport block may be allocated to the first time slot or the legacy control region. Similarly, even if the first slot is designated for a new control region, the transport block may be allocated to the legacy control region.

In some cases, up to two Transport Blocks (TBs) may be used in a multiple-input multiple-output (MIMO) system. Thus, the combined MIMO transport block size may be considered. Alternatively, when allocating MIMO transport blocks, the transport block size may be different from C_maxAnd (6) comparing.

In one aspect, a common search space control message may be transmitted in a legacy control region. Since legacy UEs may be present in the network, a legacy control region is designated for all or most of the subframes. The legacy control region and the new control region may exist in the same subframe. However, when a new control region is designated for a subframe, the number of OFDM symbols allocated to the legacy subframe can be reduced compared to the number of OFDM symbols occupied by the unused new control region. The number of occupied OFDM symbols is reduced due to control offload (off-load).

The UE may be semi-statically configured to monitor the UE-specific search space in either the legacy control region or the new control region. The UE may also be requested to monitor both the legacy control region and the new control region. The control may be sent based on a transport block size. Further, the decoding time designated for large transport blocks may be greater than the decoding time designated for small transport blocks.

In some cases, the UE-specific search space may be located in a legacy control region or a new control region in order not to increase the number of blind decodes performed by the UE. The common search space will remain located in the legacy control area.

In another aspect, the search space may be partitioned based on the aggregation size. For example, when the aggregation level is 1, the UE may first monitor two decoding hypotheses (i.e., decoding candidates) in the legacy control region and then monitor four decoding hypotheses in the new control region. Further, when the aggregation level is 2, the UE may first monitor two decoding hypotheses (i.e., decoding candidates) in the legacy control region and then monitor four decoding hypotheses in the new control region. Further, when the aggregation level is 4, the UE may first monitor one decoding hypothesis (i.e., decoding candidates) in the legacy control region and then one decoding hypothesis in the new control region. Further, when the aggregation level is 8, the UE may monitor only the legacy control region. Aggregation level dependent partitioning of decoding hypotheses (decoding candidates) may be specified in the standard or semi-statically configured for the UE. However, a common search space (e.g., a broadcast SIB (system information block)) may remain located in the legacy control region.

According to aspects of the present disclosure, existing demodulation hardware may be reused by limiting the maximum Transport Block Size (TBS) as a function of E-PDCCH duration. Furthermore, for small transport block sizes, decoding time is reduced, and thus, a new control region may be designated. For large transport block sizes, the control information may be specified in a legacy control region, since only a few UEs are scheduled due to limitations expressed in terms of cell capacity.

In some cases, the signal-to-noise ratio (SNR) is moderate when new control regions and beamforming are used for coverage extension purposes. Thus, the maximum transport block size may be limited in nature. Accordingly, the decoding time can be reduced and the use of a new control region is possible.

Fig. 9A illustrates a method 901 for monitoring a control area. At block 910, a UE (user equipment) monitors at least two different control regions in a subframe for control information. The control regions do not overlap in time. At block 912, the UE receives a subframe including control information in at least one of the two different control regions.

Fig. 9B illustrates a method 902 for limiting a transport block size. At block 920, the eNodeB determines a control region for sending control information to the recipient based on the transport block size. At block 922, the eNodeB transmits control information in the determined control region.

In one configuration, the eNodeB610 is configured for wireless communication, which includes means for determining. In one aspect, the determining means may be the controller/processor 675 and the memory 676 configured to perform the functions recited by the determining means. The eNodeB610 is also configured to include means for transmitting. In one aspect, the transmit unit may be a transmit processor 616, a modulator 618, and an antenna 620 configured to perform the functions recited by the transmit unit. In another aspect, the aforementioned means may be any module or any apparatus configured to perform the functions recited by the aforementioned means.

In one configuration, the UE 650 is configured for wireless communication, which includes means for monitoring. In one aspect, the monitoring unit may be the controller/processor 659, receive processor 656, modulator 654 and antenna 652 configured to perform the functions recited by the monitoring unit. The UE 650 is also configured to include means for receiving. In one aspect, the receiving means may be the controller/processor 659, receive processor 656, modulator 654 and antenna 652 configured to perform the functions recited by the receiving means. In another aspect, the aforementioned means may be any module or any apparatus configured to perform the functions recited by the aforementioned means.

Fig. 10 is a conceptual data flow diagram illustrating the data flow between different modules/means/components in an exemplary apparatus 1000. The apparatus 1000 includes a monitoring module 1002, the monitoring module 1002 monitoring at least two different control regions in a subframe for control information. The monitoring module 1002 monitors a control region of a subframe received via the receiving module 1006. The receiving module 1006 receives the sub-frame on signal 1010. Further, the receiving module 1006 may also receive a subframe including control information in at least one of the two different control regions. The apparatus may include additional modules that perform each of the steps of the algorithms of the aforementioned flow charts in fig. 9A and 9B. Accordingly, each step in the aforementioned flowcharts of fig. 9A and 9B may be performed by a module and the apparatus may include one or more of those modules. The modules may be one or more hardware components specifically configured to perform the claimed processes/algorithms, implemented by a processor configured to perform the claimed processes/algorithms, stored in a computer-readable medium for implementation by a processor, or some combination thereof.

Fig. 11 is a conceptual data flow diagram illustrating the data flow between different modules/means/components in an exemplary apparatus 1100. The apparatus 1100 includes a determination module 1102 that determines a control region for transmitting control information to a receiving side based on a transport block size. The determining module 1102 may then control the transmitting module 1108 to transmit control information in the determined control region. The control information may be transmitted via signal 1112, which is transmitted via transmission module 1108. The apparatus may include additional modules that perform each of the steps of the algorithms of the aforementioned flow charts in fig. 9A and 9B. Accordingly, each step in the aforementioned flowcharts of fig. 9A and 9B may be performed by a module and the apparatus may include one or more of those modules. The modules may be one or more hardware components specifically configured to perform the claimed processes/algorithms, implemented by a processor configured to perform the claimed processes/algorithms, stored in a computer-readable medium for implementation by a processor, or some combination thereof.

Fig. 12 is a diagram illustrating an example of a hardware implementation of an apparatus 1200 employing a processing system 1214. The processing system 1214 may be implemented with a bus architecture, represented generally by the bus 1224. The bus 1224 may include any number of interconnecting buses and bridges depending on the specific application of the processing system 1214 and the overall design constraints. The bus 1224 connects together various circuits including one or more processors and/or hardware modules, represented by the processor 1222, the

modules

1202, 1204, 1206, and the computer-readable medium 1226. The bus 1224 may also connect various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described in further detail.

The apparatus includes a processing system 1214 coupled to a transceiver 1230. The transceiver 1230 is coupled to one or more antennas 1220. The transceiver 1230 enables communicating with various other apparatus over a transmission medium. The processing system 1214 includes a processor 1222 coupled to a computer-readable medium 1226. The processor 1222 is responsible for general processing, including the execution of software stored on the computer-readable medium 1226. The software, when executed by the processor 1222, causes the processing system 1214 to perform the various functions described for any particular apparatus. The computer-readable medium 1226 may also be used for storing data that is manipulated by the processor 1222 when executing software.

The processing system 1214 includes: a monitoring module 1202 for monitoring at least two different control regions in a subframe for control information. The processing system 1214 further includes: a receiving module 1204 for receiving a subframe comprising control information in at least one of the two different control regions. The modules may be software modules running in the processor 1222, resident/stored in the computer readable medium 1226, one or more hardware modules coupled to the processor 1222, or some combination thereof. The processing system 1214 may be a component of the UE 650 and may include the memory 660 and/or the controller/processor 659.

Fig. 13 is a diagram illustrating an example of a hardware implementation of an apparatus 1300 employing a processing system 1314. The processing system 1314 may be implemented with a bus architecture, represented generally by the bus 1324. The bus 1324 may include any number of interconnecting buses and bridges depending on the specific application of the processing system 1314 and the overall design constraints. The bus 1324 connects together various circuits including one or more processors and/or hardware modules, represented by the processor 1322, the

modules

1302, 1304, 1306 and the computer-readable medium 1326. The bus 1324 may also connect various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described in depth.

The device includes a processing system 1314 coupled to a transceiver 1330. The transceiver 1330 is coupled to one or more antennas 1320. The transceiver 1330 enables communicating with various other apparatus over a transmission medium. The processing system 1314 includes a processor 1322 coupled to a computer-readable medium 1326. The processor 1322 is responsible for general processing, including the execution of software stored on the computer-readable medium 1326. The software, when executed by the processor 1322, causes the processing system 1314 to perform the various functions described for any particular apparatus. The computer-readable medium 1326 may also be used for storing data that is manipulated by the processor 1322 when executing software.

The processing system 1314 includes: a determination module 1302 for determining a control region for transmitting control information to a receiving side based on the transport block size. The processing system 1314 further includes: a transmitting module 1304 for transmitting control information in the determined control region. The modules may be software modules running in the processor 1322, resident/stored in the computer readable medium 1326, one or more hardware modules coupled to the processor 1322, or some combination thereof. The processing system 1314 may be a component of the eNodeB610 and may include the memory 676 and/or the controller/processor 675.

Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the disclosure herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

The various illustrative logical blocks, modules, and circuits described in connection with the disclosure herein may be implemented or performed with a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

The steps of a method or algorithm described in connection with the disclosure herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.

In one or more exemplary designs, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, includes Compact Disc (CD), laser disc, optical disc, Digital Versatile Disc (DVD), floppy disk and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method of transmitting control information to a receiving side, comprising:

determining at least one of a PDCCH control region and an ePDCCH control region for transmitting control information to a receiver based on a transport block size of a transport block to be transmitted to the receiver, wherein a maximum transport block size has a first size when the control information is included in the PDCCH control region in a first slot of a subframe, and has a second size when the control information is included in the ePDCCH control region in the first slot and a second slot of the subframe, wherein the second size is smaller than the first size, and wherein the second slot is transmitted after the first slot; and

transmitting control information to the receiving side in the determined control region.

2. The method of claim 1, wherein the determination is based on at least one of:

ePDCCH decoding time, symbol pre-processing time, Multiple Input Multiple Output (MIMO) mode, transmission rank, and User Equipment (UE) interference cancellation factors.

3. The method of claim 1, wherein the determination is based on whether the control information is intended for one receiver or more than one receiver.

4. The method of claim 1, in which the determining is based on a Radio Network Temporary Identifier (RNTI) value used to scramble the control information Cyclic Redundancy Check (CRC).

5. The method of claim 1, wherein the determined PDCCH or ePDCCH control region is at least one of a plurality of ePDCCH regions and the PDCCH.

6. The method of claim 5, wherein the plurality of ePDCCH regions comprise: a first time slot of the ePDCCH and a second time slot of the ePDCCH.

7. The method of claim 1, wherein determining is further based on an aggregation size.

8. An apparatus for transmitting control information to a receiving side, comprising:

a memory; and

at least one processor coupled to the memory, the at least one processor configured to:

9. The apparatus of claim 8, wherein the at least one processor is configured to determine based on at least one of:

enhanced physical downlink control channel (ePDCCH) decoding time, symbol pre-processing time, multiple-input multiple-output (MIMO) mode, transmission rank, and User Equipment (UE) interference cancellation factor.

10. The apparatus of claim 8, wherein the at least one processor is configured to determine based on whether the control information is intended for one receiver or more than one receiver.

11. The apparatus of claim 8, in which the at least one processor is configured to determine based on a Radio Network Temporary Identifier (RNTI) value used to scramble the control information Cyclic Redundancy Check (CRC).

12. The apparatus of claim 8, wherein the determined PDCCH or ePDCCH control region is at least one of a plurality of ePDCCH regions and the PDCCH.

13. The apparatus of claim 12, wherein the plurality of ePDCCH regions comprises: a first time slot of the ePDCCH and a second time slot of the ePDCCH.

14. The apparatus of claim 8, in which the at least one processor is configured to determine based on an aggregation size.

15. An apparatus for transmitting control information to a receiving side, comprising:

means for determining at least one of a PDCCH control region and an ePDCCH control region for transmitting control information to a receiver based on a transport block size of a transport block to be transmitted to the receiver, wherein a maximum transport block size has a first size when the control information is included in the PDCCH control region in a first slot of a subframe, and the maximum transport block size has a second size when the control information is included in the ePDCCH control region in the first and second slots of the subframe, wherein the second size is smaller than the first size, and wherein the second slot is transmitted after the first slot; and

means for transmitting control information to the receiver in the determined control region.